chore: import upstream snapshot with attribution

examples/basic/stream_text.py

@@ -0,0 +1,21 @@
+import asyncio
+
+from openai.types.responses import ResponseTextDeltaEvent
+
+from agents import Agent, Runner
+
+
+async def main():
+    agent = Agent(
+        name="Joker",
+        instructions="You are a helpful assistant.",
+    )
+
+    result = Runner.run_streamed(agent, input="Please tell me 5 jokes.")
+    async for event in result.stream_events():
+        if event.type == "raw_response_event" and isinstance(event.data, ResponseTextDeltaEvent):
+            print(event.data.delta, end="", flush=True)
+
+
+if __name__ == "__main__":
+    asyncio.run(main())